Documentarist whose celebrated films have focused almost exclusively on the struggle of workers to form unions. Kopple began making films in her clinical psychology class while at college in West Virginia and went to live among her coal-mining subjects in Kentucky to film her Oscar-winning debut, "Harlan County, U.S.A." (1976). The film chronicles the miners' violent struggle to join the United Mine Workers union and the effect of the strike on the lives of them and their families. Praised for putting a human face on a political issue, it was one of 25 films chosen by the Library of Congress to be placed on its Film Registry in 1990.

In the late 1970s Kopple began work on her first non-documentary film, a fictionalized account of textile mill worker Crystal Lee Jordan's five-year struggle to unionize the factory where she worked; the project was aborted when it conflicted with Martin Ritt's "Norma Rae" (1979), loosely based on the same incidents. Kopple, however, used much of her research for the 1983 TV film "Keeping On", also about textile mill workers' attempts to organize.

Kopple's second documentary, "American Dream" (1990), which tracks the course of a bitter meat-packers' strike at the Hormel plant in Minnesota, became legendary for the length of time it took to complete. While management in "American Dream" behaves somewhat monolithically, Kopple also uses her omnipresent camera to capture the self-doubts of, and differences between, the striking laborers. Compared to "Harlan County", "American Dream" finds a labor movement badly divided, unsure whether to trust leadership that seems both too charismatic and less than pragmatic. Kopple's film had its world premiere at the 1991 Sundance Film Festival, where it won a special jury prize, the filmmaker's trophy and the audience award as most popular film. It also earned Kopple her second Oscar for best documentary in 1990.